Project 7: Functional Programming!

Reading! !
Introduction to Computing Using Python, Section 12.3.!
Code Snippets!
The class web sites have some Python code you can use for this project:!
• in_class.py (functions created during lecture on May 21)!
• test_fp.py (unit test program)!
Programming Projects!
The project this week is to write several small Python functions that each use one or
more functional programing (FP) constructs. The grading standards for this project
are:!
• 50% for correctness (the function produces the expected results)!
• 50% for programming style (you use FP constructs where appropriate, plus other
good programming style)!
You are allowed to write additional “helper functions” if you think it will make your
code easier to understand. !
Put all of your functions in a single file named fp.py.!
1. Write a function named codes that returns a list of numeric codes for the
characters in a string. If ch is a character (i.e. a 1-letter string) the builtin function
named ord will return its character code:!
ord('A')
65
codes('Aloha')
[65, 108, 111, 104, 97]
2. Write a function named vowels that will return a string made from the vowels
(letters A, E, I, O, and U) in a string:!
vowels('Aloha')
'Aoa'
Note that the vowels are returned in order, and that case is preserved. !
CIS 211!
Spring 20143. Write a function named tokens that will split an input string into individual words
and remove the punctuation marks from the ends of the words. The result
returned from the function should be a map object; to see the individual words
pass this object in a call to list:!
m = tokens("Buy now! Only $29.95. Wait, there's more!!")
m
<map object at 0x10260cf90
list(m)
['Buy', 'now', 'Only', '29.95', 'Wait', "there's", 'more']
Hint: you can use the strip_punctuation function demonstrated in class as a
helper function.!
4. Write a function named numbers that will use your tokens function to break a line
into words and then return the tokens that contain nothing but digits:!
numbers('Want all 5? Get them now for only $99!')
['5', ’99']
5. Write a function named sq_ft that will compute the total area of a house by
adding up the areas of the individual rooms. The argument passed to sq_ft will
be a file containing the dimensions of the rooms. To test your function you can
download a file named house.txt. This is the expected result:!
sq_ft('house.txt')
1539.0
The file will have one line per room, where each line has the room name and two
numbers representing the width and depth the room, e.g.!
kitchen 10 14
laundry 4 5
...
Suggestion: define a class named Room, and define the constructor so it will
initialize an object from a string with the name and dimensions:!
r1 = Room('kitchen 10 14’)
Add a method named area that will compute the area of a room:!
r1.area()
140.0
Now your sq_ft function can create a Room object from the description of each
line in the input file and the sq_ft function call area to compute the area of each
room.!Unit Tests!
If you want to check the correctness of your codes, vowels, tokens, and numbers
functions with the unit test program download the program from the web site and run
it with this shell command:!
python3 -m unittest test_fp.py
If all your functions are working the output will be!
....
-------------------------------------------------------------
Ran 4 tests in 0.000s !
OK
Extra Credit Ideas!
• Write a function name checksum that will compute the bitwise exclusive OR of all
the binary codes in a string. For example, here are the individual codes of the
letters in ‘Aloha’ (displayed in hexadecimal):!
for x in 'Aloha':
... print("{:0X}".format(ord(x)))
...
41
6C
6F
68
61
Here is the checksum, also displayed in hex:!
print("{:0X}".format(checksum('Aloha')))
4B